Throttle DODGE RAM 1500 1998 2.G Owner's Manual

board hardware, the cluster overlay, or the EMIC
housing are damaged or faulty, the entire EMIC mod-
ule must be replaced. The cluster lens, hood and
mask unit and the individual incandescent lamp
bulbs with holders are available for individual ser-
vice replacement.
OPERATION
The ElectroMechanical Instrument Cluster (EMIC)
in this model also includes the hardware and soft-
ware necessary to serve as the electronic body control
module and is sometimes referred to as the Cab
Compartment Node or CCN. The following informa-
tion deals primarily with the instrument cluster
functions of this unit. Additional details of the elec-
tronic body control functions of this unit may be
found within the service information for the system
or component that the EMIC controls. For example:
Additional details of the audible warning functions ofthe EMIC are found within the Chime/Buzzer service
information.
The EMIC is designed to allow the vehicle operator
to monitor the conditions of many of the vehicle com-
ponents and operating systems. The gauges and indi-
cators in the EMIC provide valuable information
about the various standard and optional powertrains,
fuel and emissions systems, cooling systems, lighting
systems, safety systems and many other convenience
items. The EMIC is installed in the instrument panel
so that all of these monitors can be easily viewed by
the vehicle operator when driving, while still allow-
ing relative ease of access for service. The micropro-
cessor-based EMIC hardware and software uses
various inputs to control the gauges and indicators
visible on the face of the cluster. Some of these
inputs are hard wired, but most are in the form of
electronic messages that are transmitted by other
electronic modules over the Programmable Communi-
cations Interface (PCI) data bus network. (Refer to 8
Fig. 3 Gauges & Indicators - Gasoline Engine
1 - MALFUNCTION INDICATOR LAMP 13 - ELECTRONIC THROTTLE CONTROL (ETC) INDICATOR
2 - VOLTAGE GAUGE 14 - ENGINE TEMPERATURE GAUGE
3 - LEFT TURN INDICATOR 15 - SECURITY INDICATOR
4 - TACHOMETER 16 - GEAR SELECTOR INDICATOR DISPLAY (INCLUDES
CRUISE & UPSHIFT INDICATORS)
5 - AIRBAG INDICATOR 17 - CHECK GAUGES INDICATOR
6 - HIGH BEAM INDICATOR 18 - BRAKE INDICATOR
7 - SEATBELT INDICATOR 19 - ABS INDICATOR
8 - SPEEDOMETER 20 - ODOMETER/TRIP ODOMETER DISPLAY (INCLUDES
ENGINE HOURS, WASHER FLUID, LAMP OUTAGE, TOW/HAUL
& SERVICE 4x4 INDICATORS)
9 - RIGHT TURN INDICATOR 21 - ODOMETER/TRIP ODOMETER SWITCH BUTTON
10 - OIL PRESSURE GAUGE 22 - FUEL GAUGE
11 - CARGO LAMP INDICATOR 23 - LOW FUEL INDICATOR
12 - DOOR AJAR INDICATOR 24 - TRANSMISSION OVERTEMP INDICATOR
8J - 6 INSTRUMENT CLUSTERDR
INSTRUMENT CLUSTER (Continued)

CAUTION: Instrument clusters used in this model
automatically configure themselves for compatibil-
ity with the features and optional equipment in the
vehicle in which they are initially installed. The
instrument cluster is programmed to do this by
embedding the Vehicle Identification Number (VIN)
and other information critical to proper cluster
operation into electronic memory. This embedded
information is learned through electronic messages
received from other electronic modules in the vehi-
cle over the Programmable Communications Inter-
face (PCI) data bus, and through certain hard wired
inputs received when the cluster is connected to
the vehicle electrically. Once configured, the instru-
ment cluster memory may be irreparably damaged
and certain irreversible configuration errors may
occur if the cluster is connected electrically to
another vehicle; or, if an electronic module from
another vehicle is connected that provides data to
the instrument cluster (including odometer values)
that conflicts with that which was previously
learned and stored. Therefore, the practice of
exchanging (swapping) instrument clusters and
other electronic modules in this vehicle with those
removed from another vehicle must always be
avoided. Failure to observe this caution may result
in instrument cluster damage, which is not reim-
bursable under the terms of the product warranty.
Service replacement instrument clusters are pro-
vided with the correct VIN, and the certified odom-
eter and engine hours values embedded into cluster
memory, but will otherwise be automatically config-
ured for compatibility with the features and optional
equipment in the vehicle in which they are initially
installed.
NOTE: Certain indicators in this instrument cluster
are automatically configured. This feature allows
those indicators to be activated or deactivated for
compatibility with certain optional equipment. If the
problem being diagnosed involves improper illumi-
nation of the cruise indicator, the electronic throttle
control indicator, the service four-wheel drive indi-
cator, the tow/haul indicator, the transmission over-
temp indicator, the upshift indicator, the security
indicator or the gear selector indicator, disconnect
and isolate the battery negative cable. After about
five minutes, reconnect the battery negative cable
and turn the ignition switch to the On position. The
instrument cluster should automatically relearn the
equipment in the vehicle and properly configure the
configurable indicators accordingly.PRELIMINARY DIAGNOSIS
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.
(1) Check the fused B(+) fuse (Fuse 51 - 20
ampere) in the Integrated Power Module (IPM). If
OK, go to Step 2. If not OK, repair the shorted circuit
or component as required and replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
(Fuse 51 - 20 ampere) in the IPM. If OK, go to Step
3. If not OK, repair the open fused B(+) circuit
between the IPM and the battery as required.
(3) Disconnect and isolate the battery negative
cable. Remove the instrument cluster. Reconnect the
battery negative cable. Check for battery voltage at
the fused B(+) circuit cavity of the instrument panel
wire harness connector (Connector C1) for the instru-
ment cluster. If OK, go to Step 4. If not OK, repair
the open fused B(+) circuit between the instrument
cluster and the IPM as required.
(4) Check for continuity between the signal ground
circuit cavity of the instrument panel wire harness
connector (Connector C1) for the instrument cluster
and a good ground. There should be continuity. If
OK, refer to ACTUATOR TEST. If not OK, repair the
open ground circuit to ground (G202) as required.
DRINSTRUMENT CLUSTER 8J - 11
INSTRUMENT CLUSTER (Continued)

NOTE: Certain indicators in this instrument cluster
are automatically configured. This feature allows
those indicators to be activated or deactivated for
compatibility with certain optional equipment. If the
problem being diagnosed involves improper illumi-
nation of the cruise indicator, the electronic throttle
control indicator, the service four-wheel drive indi-
cator, the tow/haul indicator, the transmission over-
temp indicator, the upshift indicator, the security
indicator or the gear selector indicator, disconnect
and isolate the battery negative cable. After about
five minutes, reconnect the battery negative cable
and turn the ignition switch to the On position. The
instrument cluster should automatically relearn the
equipment in the vehicle and properly configure the
configurable indicators accordingly.
ABS INDICATOR
DESCRIPTION
An Antilock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters (Fig. 8).
However, the instrument cluster can be programmed
to disable this indicator on vehicles that are not
equipped with the ABS or Rear Wheel Anti-Lock
(RWAL) brake systems, which are not available in
some markets. On vehicles equipped with a gasoline
engine, the ABS indicator is located near the lower
edge of the instrument cluster, between the tachom-
eter and the speedometer. On vehicles equipped with
a diesel engine, the ABS indicator is located on the
right side of the instrument cluster, to the right of
the engine temperature gauge. The ABS indicator
consists of a stencil-like cutout of the International
Control and Display Symbol icon for ªFailure of Anti-
lock Braking Systemº in the opaque layer of the
instrument cluster overlay. The dark outer layer of
the overlay prevents the indicator from being clearly
visible when it is not illuminated. An amber Light
Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the icon to appear
in amber through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by the LED, which is soldered onto the
instrument cluster electronic circuit board. The ABS
indicator is serviced as a unit with the instrument
cluster.
OPERATION
The ABS indicator gives an indication to the vehi-
cle operator when the ABS system is faulty or inop-
erative. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Programmable Communications Interface
(PCI) data bus. The ABS indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the LED will always be off when the ignition switch
is in any position except On or Start. The LED only
illuminates when it is provided a path to ground by
the instrument cluster transistor. The instrument
cluster will turn on the ABS indicator for the follow-
ing reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ABS indicator is illu-
minated by the cluster for about two seconds as a
bulb test.
²ABS Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the CAB, the
ABS indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Communication Error- If the cluster receives
no lamp-on or lamp-off messages from the CAB for
three consecutive seconds, the ABS indicator is illu-
minated. The indicator remains illuminated until the
cluster receives a valid message from the CAB, or
until the ignition switch is turned to the Off position,
whichever occurs first.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the ABS indica-
tor will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
²ABS Diagnostic Test- The ABS indicator is
blinked on and off by lamp-on and lamp-off messages
from the CAB during the performance of the ABS
diagnostic tests.
The CAB continually monitors the ABS circuits
and sensors to decide whether the system is in good
operating condition. The CAB then sends the proper
lamp-on or lamp-off messages to the instrument clus-
ter. If the CAB sends a lamp-on message after the
bulb test, it indicates that the CAB has detected a
system malfunction and/or that the ABS system has
become inoperative. The CAB will store a Diagnostic
Trouble Code (DTC) for any malfunction it detects.
Fig. 8 ABS Indicator
DRINSTRUMENT CLUSTER 8J - 17
INSTRUMENT CLUSTER (Continued)

²Actuator Test- Each time the cluster is put
through the actuator test, the engine coolant temper-
ature gauge needle will be swept to several calibra-
tion points on the gauge scale in a prescribed
sequence in order to confirm the functionality of the
gauge and the cluster control circuitry.
On vehicles with a gasoline engine, the PCM con-
tinually monitors the engine coolant temperature
sensor to determine the engine operating tempera-
ture. On vehicles with a diesel engine, the ECM con-
tinually monitors the engine coolant temperature
sensor to determine the engine operating tempera-
ture. The PCM or ECM then sends the proper engine
coolant temperature messages to the instrument
cluster. For further diagnosis of the engine coolant
temperature gauge or the instrument cluster cir-
cuitry that controls the gauge, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). If the instrument cluster turns on
the check gauges indicator due to a high engine tem-
perature gauge reading, it may indicate that the
engine or the engine cooling system requires service.
For proper diagnosis of the engine coolant tempera-
ture sensor, the PCM, the ECM, the PCI data bus, or
the electronic message inputs to the instrument clus-
ter that control the engine coolant temperature
gauge, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
ETC INDICATOR
DESCRIPTION
An Electronic Throttle Control (ETC) indicator is
standard equipment on all gasoline engine instru-
ment clusters (Fig. 16). However, on vehicles not
equipped with the optional 5.7 liter gasoline engine,
this indicator is electronically disabled. The ETC
indicator is located on the right side of the instru-
ment cluster, to the right of the engine temperature
gauge. The ETC indicator consists of a stencil-like
cutout of the International Control and Display Sym-
bol icon for ªElectronic Throttle Controlº in the
opaque layer of the instrument cluster overlay. The
dark outer layer of the overlay prevents the indicator
from being clearly visible when it is not illuminated.
A red Light Emitting Diode (LED) behind the cutout
in the opaque layer of the overlay causes the icon to
appear in red through the translucent outer layer of
the overlay when the indicator is illuminated from
behind by the LED, which is soldered onto theinstrument cluster electronic circuit board. The ETC
indicator is serviced as a unit with the instrument
cluster.
OPERATION
The Electronic Throttle Control (ETC) indicator
gives an indication to the vehicle operator when the
ETC system is faulty or inoperative. The ETC indi-
cator is controlled by a transistor on the instrument
cluster circuit board based upon cluster programming
and electronic messages received by the cluster from
the Powertrain Control Module (PCM) over the Pro-
grammable Communications Interface (PCI) data
bus. The ETC indicator Light Emitting Diode (LED)
is completely controlled by the instrument cluster
logic circuit, and that logic will only allow this indi-
cator to operate when the instrument cluster receives
a battery current input on the fused ignition switch
output (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the ETC indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ETC indicator is illu-
minated for about six seconds. The entire six second
bulb test is a function of the PCM.
²ETC Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the PCM, the
ETC indicator will be illuminated. The indicator can
be flashed on and off, or illuminated solid, as dic-
tated by the PCM message. The indicator remains
illuminated solid or continues to flash for about
twelve seconds or until the cluster receives a lamp-off
message from the PCM, whichever is longer. If the
indicator is illuminated solid with the engine run-
ning the vehicle will usually remain drivable. If the
indicator is flashing with the engine running the
vehicle may require towing. A flashing indicator
means the ETC system requires immediate service.
²Communication Error- If the cluster receives
no ETC lamp messages for three consecutive seconds,
the ETC indicator is illuminated. The indicator
remains illuminated until the cluster receives a sin-
gle lamp-off message from the PCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the ETC indicator will be
turned on, then off again during the bulb check por-
tion of the test to confirm the functionality of the
LED and the cluster control circuitry. The actuator
test illumination of the ETC indicator is a function of
the PCM.
The PCM continually monitors the ETC system cir-
cuits and sensors to decide whether the system is in
good operating condition. The PCM then sends the
Fig. 16 ETC Indicator
DRINSTRUMENT CLUSTER 8J - 25
ENGINE TEMPERATURE GAUGE (Continued)

(5) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoir
and engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
5.7 Gas
Vacuum is not used for any part of the speed con-
trol system if equipped with a 5.7L V-8 engine.
5.9L Diesel Engine With Manual Trans.
Vacuum is not used for any part of the speed con-
trol system if equipped with a diesel engine and a
manual transmission.
5.9L Diesel Engines With Automatic Trans.
If equipped with a diesel powered engine and an
automatic transmission, an electric vacuum pump
and vacuum lines are used to supply vacuum to the
speed control servo. A vacuum reservoir is not used.
DIAGNOSIS AND TESTING - ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer. Speed-ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Instrument
Cluster for speedometer diagnosis.
If a road test verifies a system problem and the
speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose, damaged or corroded electrical connec-
tions at the servo (if used). Corrosion should be
removed from electrical terminals and a light coating
of Mopar MultiPurpose Grease, or equivalent,
applied.
²Leaking vacuum reservoir (if used).
²Loose or leaking vacuum hoses or connections (if
used).
²Defective one-way vacuum check valve (if used).
²Secure attachment of both ends of the speed con-
trol servo cable (if used).
²Smooth operation of throttle linkage (if used)
and throttle body air valve.
²Failed speed control servo (if used). Do the servo
vacuum test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
SPECIFICATIONS
TORQUE - SPEED CONTROL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Servo Mounting Bracket-
to-Servo Nuts7-60
Servo Mounting Bracket-
to-Battery Tray Screws4-30
Speed Control Switch
Mounting Screws1.7 - 15
Vacuum Reservoir
Mounting Nuts3-20
DRSPEED CONTROL 8P - 3
SPEED CONTROL (Continued)

CABLE
DESCRIPTION
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage. This cable is used with
3.7L/4.7L gas powered engines only. It is also used if
equipped with a 5.9L diesel engine equipped with an
automatic transmission.
A speed control servo cableis not usedif equipped
with either a 5.9L diesel engine equipped with a
manual transmission, or any 5.7L engine/transmis-
sion combinations.
OPERATION
This cable causes the throttle control linkage to
open or close the throttle valve in response to move-
ment of the vacuum servo diaphragm.
REMOVAL
3.7L / 4.7L GAS
(1) Disconnect negative battery cable at battery.
(2) Remove air intake tube at top of throttle body.
The accelerator cable must be partially removed to
gain access to speed control cable.
(3) Hold throttle in wide open position. While held
in this position, slide throttle cable pin (Fig. 1) from
throttle body bellcrank.
(4) Using a pick or small screwdriver, press release
tab (Fig. 2) to release plastic cable mount from
bracket.Press on tab only enough to release
cable from bracket. If tab is pressed too much,
it will be broken.Slide plastic mount (Fig. 2)
towards right side of vehicle to remove throttle cable
from throttle body bracket.
(5) Using finger pressure only, disconnect servo
cable connector (Fig. 3) at throttle body bellcrank pin
by pushing connector off bellcrank pin towards front
of vehicle.DO NOT try to pull connector off per-
pendicular to the bellcrank pin. Connector will
be broken.
(6) Slide speed control cable plastic mount towards
right of vehicle to remove cable from throttle body
bracket (Fig. 4).
(7) Remove servo cable from servo. Refer to Servo
Removal/Installation.
5.9L Diesel Ð Auto. Trans.
(1) Disconnect both negative battery cables at both
batteries.
(2) Remove cable/lever/linkage cover. Refer to
Speed Control Servo Removal/Installation.
(3) Remove (disconnect) servo cable from servo.
Refer to Speed Control Servo Removal/Installation.(4) Using finger pressure only, disconnect end of
servo cable from throttle lever pin by pulling forward
on connector while holding lever rearward (Fig. 5).
DO NOT try to pull connector off perpendicular
to lever pin. Connector will be broken.
(5) Squeeze 2 pinch tabs (Fig. 5) on sides of speed
control cable at mounting bracket and push cable
rearward out of bracket.
Fig. 1 THROTTLE CABLE PIN - 3.7L / 4.7L
1 - THROTTLE CABLE PIN
2 - THROTTLE BODY BELLCRANK
3 - PUSH UP HERE
Fig. 2 THROTTLE CABLE RELEASE TAB - 3.7L /
4.7L
1 - THROTTLE CABLE
2 - RELEASE TAB
3 - PICK OR SCREWDRIVER
4 - PLASTIC CABLE MOUNT
8P - 4 SPEED CONTROLDR

(6) Remove cable from vehicle.
INSTALLATION
3.7L / 4.7L Gas
(1) Install end of cable to speed control servo.
Refer to Servo Removal/Installation.(2) Slide speed control cable plastic mount into
throttle body bracket.
(3) Install speed control cable connector onto throt-
tle body bellcrank pin (push rearward to snap into
location).
(4) Slide throttle (accelerator) cable plastic mount
into throttle body bracket. Continue sliding until
cable release tab is aligned to hole in throttle body
mounting bracket.
(5) While holding throttle to wide open position,
place throttle cable pin into throttle body bellcrank.
(6) Install air intake tube to top of throttle body.
(7) Connect negative battery cable at battery.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
5.9L Diesel Ð Auto. Trans.
(1) Install (connect) end of speed control servo
cable to speed control servo. Refer to Speed Control
Servo Removal/Installation.
(2) Install cable through mounting hole on mount-
ing bracket. Cable snaps into bracket.
(3) Connect servo cable to throttle lever by push-
ing cable connector rearward onto lever pin while
holding lever forward.
(4) Connect negative battery cables to both batter-
ies.
Fig. 3 SPEED CONTROL CABLE AT BELLCRANK -
3.7L / 4.7L
1 - THROTTLE BODY BELLCRANK
2 - SPEED CONTROL CABLE CONNECTOR
Fig. 4 SPEED CONTROL CABLE AT BRACKET - 3.7L
/ 4.7L
1 - THROTTLE CABLE BRACKET
2 - PLASTIC CABLE MOUNT
3 - SPEED CONTROL CABLE
Fig. 5 SERVO CABLE AT THROTTLE LEVER Ð 5.9L
DIESEL
1 - PINCH (2) TABS
2 - CABLE MOUNTING BRACKET
3 - PINCH TABS (2)
4 - OFF
5 - THROTTLE CABLE
6 - THROTTLE LEVER
7 - THROTTLE LEVER PIN
8 - OFF
9 - CONNECTOR
10 - SPEED CONTROL CABLE
DRSPEED CONTROL 8P - 5
CABLE (Continued)

(5) Before starting engine, operate accelerator
pedal to check for any binding.
(6) Install cable/lever cover.
SERVO
DESCRIPTION
A speed control servo is not used with any
5.7L V-8 engine, or with the 5.9L diesel engine
when equipped with a manual transmission.
The speed control servo is attached to the bottom
of the battery tray.
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The solenoid valve body con-
tains three solenoids:
²Vacuum
²Vent
²Dump
The vacuum chamber contains a diaphragm with a
cable attached to control the throttle linkage.
OPERATION
A speed control servo is not used with any
5.7L V-8 engine, or with the 5.9L diesel engine
when equipped with a manual transmission.
The following information applies only to
vehicles equipped with a mechanical servo.
When/if a servo is used on gasoline powered vehi-
cles, the Powertrain Control Module (PCM) controls
the solenoid valve body. When/if a servo is used on
certain diesel powered vehicles, the Engine Control
Module (ECM) controls the solenoid valve body. The
solenoid valve body controls the application and
release of vacuum to the diaphragm of the vacuum
servo. The servo unit cannot be repaired and is ser-
viced only as a complete assembly.
Power is supplied to the servo's by the PCM/ECM
through the brake switch. The PCM/ECM controls
the ground path for the vacuum and vent solenoids.
The dump solenoid is energized anytime it receives
power. If power to the dump solenoid is interrupted,
the solenoid dumps vacuum in the servo. This pro-
vides a safety backup to the vent and vacuum sole-
noids.
The vacuum and vent solenoids must be grounded
at the PCM/ECM to operate. When the PCM/ECM
grounds the vacuum servo solenoid, the solenoid
allows vacuum to enter the servo and pull open the
throttle plate using the cable. When the PCM/ECM
breaks the ground, the solenoid closes and no more
vacuum is allowed to enter the servo. The PCM/ECM
also operates the vent solenoid via ground. The vent
solenoid opens and closes a passage to bleed or hold
vacuum in the servo as required.The PCM/ECM duty cycles the vacuum and vent
solenoids to maintain the set speed, or to accelerate
and decelerate the vehicle. To increase throttle open-
ing, the PCM/ECM grounds the vacuum and vent
solenoids. To decrease throttle opening, the PCM/
ECM removes the grounds from the vacuum and
vent solenoids. When the brake is released, if vehicle
speed exceeds 30 mph to resume, 35 mph to set, and
the RES/ACCEL switch has been depressed, ground
for the vent and vacuum circuits is restored.
REMOVAL
The speed control servo assembly is attached to the
bottom of the battery tray (Fig. 6).
(1) Disconnect negative battery cable at battery
(both cables at both batteries if diesel).
(2) To gain access to servo, remove plastic wheel-
house splash shield over left-front wheel.
(3) Disconnect vacuum line at servo (Fig. 6).
(4) Disconnect electrical connector at servo (Fig. 6).
(5) Remove 3 servo mounting screws (Fig. 6).
Depending on engine application, different sets of
mounting lugs (Fig. 6) are used to support servo to
battery tray. While removing, note proper lugs.
(6) Disconnect servo cable at throttle body. Refer to
Servo Cable Removal/Installation.
(7) Remove 2 mounting nuts holding servo cable
sleeve to bracket (Fig. 7).
(8) Pull speed control cable sleeve and servo away
from servo mounting bracket to expose cable retain-
ing clip (Fig. 7) and remove clip. Note: The servo
mounting bracket displayed in (Fig. 7) is a typical
bracket and may/may not be applicable to this model
vehicle.
(9) Remove servo from mounting bracket. While
removing, note orientation of servo to bracket.
INSTALLATION
(1) Position servo to mounting bracket (Fig. 7).
(2) Align hole in cable connector with hole in servo
pin. Install cable-to-servo retaining clip (Fig. 7).
(3) Insert servo mounting studs through holes in
servo mounting bracket.
(4) Install 2 servo-to-mounting bracket nuts and
tighten. Refer to torque specifications.
(5) Position servo assembly to correct mounting
lugs on battery tray (Fig. 6) and install 3 screws.
Tighten 3 screws. Refer to torque specifications.
(6) Connect vacuum line at servo.
(7) Connect electrical connector at servo.
(8) Connect servo cable to throttle body. Refer to
servo Cable Removal/Installation.
(9) Install left-front wheel-well liner.
(10) Connect negative battery cable to battery
(connect both cables if diesel).
8P - 6 SPEED CONTROLDR
CABLE (Continued)

8W-02 COMPONENT INDEX
Component Page
A/C Compressor Clutch................. 8W-42
A/C Compressor Clutch Relay............ 8W-42
A/C Pressure Transducer................ 8W-42
A/C-Heater Control.................... 8W-42
Accelerator Pedal Position Sensor......... 8W-30
Adjustable Pedal Motor................. 8W-30
Adjustable Pedal Relay................. 8W-30
Adjustable Pedal Switch................ 8W-30
Airbag Control Module................. 8W-43
Airbag-Squibs........................ 8W-43
Airbag-Curtains....................... 8W-43
Airbag-Passenger On/Off Switch.......... 8W-43
Ambient Temperature Sensor............ 8W-49
Amplifier Audio....................... 8W-47
Ashtray Lamp........................ 8W-44
Auto Shut Down Relay................. 8W-30
Automatic Day/Night Mirror.......... 8W-49, 55
Auxiliary Battery..................... 8W-20
Backup Lamp Switch.................. 8W-51
Battery............................. 8W-20
Battery Temperature Sensor............. 8W-30
Blend Door Actuators.................. 8W-42
Blower Motor......................... 8W-42
Blower Motor Resistor Block............. 8W-42
Brake Fluid Level Switch............ 8W-34, 35
Brake Lamp Switch.................... 8W-33
Brake Transmission Shift Interlock
Solenoid........................... 8W-40
Camshaft Position Sensor............... 8W-30
Capacitor............................ 8W-30
Center High Mounted Stop Lamp-
Aftermarket........................ 8W-51
Center High Mounted Stop Lamp/Cargo
Lamp.......................... 8W-44, 51
Cigar Lighter Outlet................... 8W-41
Circuit Breaker....................... 8W-10
Clearance Lamps...................... 8W-50
Clockspring................. 8W-33, 41, 43, 47
Clutch Interlock Brake Switch........... 8W-21
Coil On Plugs........................ 8W-30
Compass/Mini-Trip Computer............ 8W-49
Condenser Fan....................... 8W-42
Condenser Fan Relay.................. 8W-42
Controller Antilock Brake............ 8W-34, 35
Crankshaft Position Sensor.............. 8W-30
Cylinder Lock Switch-Driver............. 8W-61
Data Link Connector................... 8W-18
Data Link Connector-Engine............. 8W-18
Dome Lamp....................... 8W-44, 49
Door Ajar Switches.................... 8W-40
Door Lock Motor/Ajar Switches........ 8W-40, 61
Door Lock Switch-Passenger............. 8W-61Component Page
Door Module................... 8W-60, 61, 62
EGR Solenoid........................ 8W-30
Electric Backlight..................... 8W-48
Electric Brake Provision................ 8W-54
Electronic Throttle Control Module........ 8W-30
Engine Control Module................. 8W-30
Engine Coolant Temperature Sensor....... 8W-30
Engine Oil Pressure Switch.............. 8W-30
EVAP/Purge Solenoid.................. 8W-30
Evaporator Temperature Sensor.......... 8W-42
Fender Lamps........................ 8W-51
Fog Lamp Relay...................... 8W-50
Fog Lamps.......................... 8W-50
Front Control Module.................. 8W-10
Fuel Control Actuator.................. 8W-30
Fuel Heater.......................... 8W-30
Fuel Heater Relay..................... 8W-30
Fuel Injector Packs.................... 8W-30
Fuel Injectors........................ 8W-30
Fuel Pump Module.................... 8W-30
Fuel Pump Motor..................... 8W-30
Fuel Pump Relay...................... 8W-30
Fuses............................ 8W-10, 33
Fusible Link......................... 8W-10
Generator........................... 8W-20
Glove Box Lamp And Switch............. 8W-44
Grounds............................ 8W-15
Hands Free Module.................... 8W-55
Headlamp Switch.................. 8W-40, 50
Headlamps.......................... 8W-50
Heated Mirror Relay................... 8W-62
Heated Seat Cushions.................. 8W-63
Horn Relay.......................... 8W-41
Horn Switch......................... 8W-41
Horn-High Note....................... 8W-41
Horn-Low Note....................... 8W-41
Idle Air Control Motor.................. 8W-30
Ignition Switch....................... 8W-10
Inlet Air Temperature Sensor............ 8W-30
Input Speed Sensor.................... 8W-31
Instrument Cluster.................... 8W-40
Intake Air Heater Relays............... 8W-30
Intake Air Temperature Sensor........... 8W-30
Intake Air Temperature/Manifold Absolute
Pressure Sensor..................... 8W-30
Integrated Power Module............... 8W-10
Knock Sensosr........................ 8W-30
License Lamps....................... 8W-51
Lift Pump Motor...................... 8W-30
Line Pressure Sensor................ 8W-30, 31
Lumbar Motors....................... 8W-63
Lumbar Switch....................... 8W-63
DR8W-02 COMPONENT INDEX 8W - 02 - 1

Component Page
Manifold Absolute Pressure Sensor........ 8W-30
Mode Door Actuators................... 8W-42
Multi-Function Switch............ 8W-40, 52, 53
Natural Vacuum Leak Detection Assembly . . 8W-30
Output Speed Sensor................... 8W-31
Overhead Map/Reading Lamp......... 8W-44, 49
Oxygen Sensor Downstream Relay........ 8W-30
Oxygen Sensors....................... 8W-30
Park Brake Switch.................... 8W-40
Park Lamp Relay................... 8W-50, 52
Park/Turn Signal Lamps............. 8W-50, 52
Power Mirrors........................ 8W-62
Power Outlets........................ 8W-41
Power Seat Motors.................... 8W-63
Power Seat Switches................... 8W-63
Power Steering Pressure Switch.......... 8W-30
Power Window Circuit Breaker........... 8W-10
Power Window Motors.................. 8W-60
Power Window Switches................ 8W-60
Powertrain Control Module.............. 8W-30
PTCS............................... 8W-10
PTO Switch.......................... 8W-30
Radio............................... 8W-47
Rear Window Defogger Relay............ 8W-48
Recirculation Door Actuator............. 8W-42
Remote Radio Switches................. 8W-47
Seat Belt Pretensioners................. 8W-43
Seat Belt Switch-Driver................ 8W-40
Seat Belt Tensioner Reducer............. 8W-40
Seat Heater Interface Module............ 8W-63
Sentry Key Immobilizer Module.......... 8W-39
Side Impact Sensors................... 8W-43
Speakers............................ 8W-47Component Page
Speed Control Servo................... 8W-33
Speed Control Switches................. 8W-33
Splices.............................. 8W-70
Starter Motor........................ 8W-21
Starter Motor Relay................... 8W-21
Tail/Stop Lamp....................... 8W-52
Tail/Stop/Turn Signal Lamps.......... 8W-51, 52
Tail/Turn Lamp....................... 8W-52
Tailgate Lamp........................ 8W-51
Throttle Position Sensor................ 8W-30
Tow/Haul Overdrive Switch........... 8W-30, 31
Trailer Tow Connectors................. 8W-54
Trailer Tow Relays.................... 8W-54
Transfer Case Control Module............ 8W-31
Transfer Case Mode Sensor.............. 8W-31
Transfer Case Selector Switch............ 8W-31
Transfer Case Shift Motor............... 8W-31
Transmission Control Relay............. 8W-31
Transmission Range Sensor.............. 8W-31
Transmission Solenoid Assembly.......... 8W-31
Transmission Solenoid/TRS Assembly...... 8W-31
Underhood Lamp...................... 8W-44
Vacuum Pump........................ 8W-30
Vistronic Fan Drive................. 8W-30, 70
Washer Fluid Level Switch.............. 8W-53
Washer Pump Motor-Front.............. 8W-53
Water In Fuel Sensor.................. 8W-30
Wheel Speed Sensors................... 8W-35
Wiper High/Low Relay................. 8W-53
Wiper Motor-Front.................... 8W-53
Wiper On/Off Relay.................... 8W-53
8W - 02 - 2 8W-02 COMPONENT INDEXDR